// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package work

import (
	"bytes"
	"cmd/internal/objabi"
	"cmd/internal/sys"
	"fmt"
	"math/rand"
	"testing"
	"time"
	"unicode/utf8"
)

func TestEncodeArgs(t *testing.T) {
	t.Parallel()
	tests := []struct {
		arg, want string
	}{
		{"", ""},
		{"hello", "hello"},
		{"hello\n", "hello\\n"},
		{"hello\\", "hello\\\\"},
		{"hello\nthere", "hello\\nthere"},
		{"\\\n", "\\\\\\n"},
	}
	for _, test := range tests {
		if got := encodeArg(test.arg); got != test.want {
			t.Errorf("encodeArg(%q) = %q, want %q", test.arg, got, test.want)
		}
	}
}

func TestEncodeDecode(t *testing.T) {
	t.Parallel()
	tests := []string{
		"",
		"hello",
		"hello\\there",
		"hello\nthere",
		"hello 中国",
		"hello \n中\\国",
	}
	for _, arg := range tests {
		if got := objabi.DecodeArg(encodeArg(arg)); got != arg {
			t.Errorf("objabi.DecodeArg(encodeArg(%q)) = %q", arg, got)
		}
	}
}

func TestEncodeDecodeFuzz(t *testing.T) {
	if testing.Short() {
		t.Skip("fuzz test is slow")
	}
	t.Parallel()

	nRunes := sys.ExecArgLengthLimit + 100
	rBuffer := make([]rune, nRunes)
	buf := bytes.NewBuffer([]byte(string(rBuffer)))

	seed := time.Now().UnixNano()
	t.Logf("rand seed: %v", seed)
	rng := rand.New(rand.NewSource(seed))

	for i := 0; i < 50; i++ {
		// Generate a random string of runes.
		buf.Reset()
		for buf.Len() < sys.ExecArgLengthLimit+1 {
			var r rune
			for {
				r = rune(rng.Intn(utf8.MaxRune + 1))
				if utf8.ValidRune(r) {
					break
				}
			}
			fmt.Fprintf(buf, "%c", r)
		}
		arg := buf.String()

		if got := objabi.DecodeArg(encodeArg(arg)); got != arg {
			t.Errorf("[%d] objabi.DecodeArg(encodeArg(%q)) = %q [seed: %v]", i, arg, got, seed)
		}
	}
}